public int Test_comparison(string a, string b)
{
var aParts = a.Split(':');
var bParts = b.Split(':');
var aFee = new Fee(new Asset(aParts[0]), UMoney.Parse(aParts[1]));
var bFee = new Fee(new Asset(bParts[0]), UMoney.Parse(bParts[1]));
return(aFee.CompareTo(bFee));
}